SPARK-4682 [CORE] Consolidate various 'Clock' classes

Another one from JoshRosen 's wish list. The first commit is much smaller and removes 2 of the 4 Clock classes. The second is much larger, necessary for consolidating the streaming one. I put together implementations in the way that seemed simplest. Almost all the change is standardizing class and method names.

Author: Sean Owen <[email protected]>

Closes apache#4514 from srowen/SPARK-4682 and squashes the following commits:

5ed3a03 [Sean Owen] Javadoc Clock classes; make ManualClock private[spark]
169dd13 [Sean Owen] Add support for legacy org.apache.spark.streaming clock class names
277785a [Sean Owen] Reduce the net change in this patch by reversing some unnecessary syntax changes along the way
b5e53df [Sean Owen] FakeClock -> ManualClock; getTime() -> getTimeMillis()
160863a [Sean Owen] Consolidate Streaming Clock class into common util Clock
7c956b2 [Sean Owen] Consolidate Clocks except for Streaming Clock

Author: srowen

core/src/main/scala/org/apache/spark/ExecutorAllocationManager.scala

@@ -20,6 +20,7 @@ package org.apache.spark
 import scala.collection.mutable
 
 import org.apache.spark.scheduler._
+import org.apache.spark.util.{SystemClock, Clock}
 
 /**
  * An agent that dynamically allocates and removes executors based on the workload.
@@ -123,7 +124,7 @@ private[spark] class ExecutorAllocationManager(
   private val intervalMillis: Long = 100
 
   // Clock used to schedule when executors should be added and removed
-  private var clock: Clock = new RealClock
+  private var clock: Clock = new SystemClock()
 
   // Listener for Spark events that impact the allocation policy
   private val listener = new ExecutorAllocationListener
@@ -588,28 +589,3 @@ private[spark] class ExecutorAllocationManager(
 private object ExecutorAllocationManager {
   val NOT_SET = Long.MaxValue
 }
-
-/**
- * An abstract clock for measuring elapsed time.
- */
-private trait Clock {
-  def getTimeMillis: Long
-}
-
-/**
- * A clock backed by a monotonically increasing time source.
- * The time returned by this clock does not correspond to any notion of wall-clock time.
- */
-private class RealClock extends Clock {
-  override def getTimeMillis: Long = System.nanoTime / (1000 * 1000)
-}
-
-/**
- * A clock that allows the caller to customize the time.
- * This is used mainly for testing.
- */
-private class TestClock(startTimeMillis: Long) extends Clock {
-  private var time: Long = startTimeMillis
-  override def getTimeMillis: Long = time
-  def tick(ms: Long): Unit = { time += ms }
-}

core/src/main/scala/org/apache/spark/deploy/worker/DriverRunner.scala

@@ -20,19 +20,18 @@ package org.apache.spark.deploy.worker
 import java.io._
 
 import scala.collection.JavaConversions._
-import scala.collection.Map
 
 import akka.actor.ActorRef
 import com.google.common.base.Charsets.UTF_8
 import com.google.common.io.Files
-import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.{FileUtil, Path}
 
 import org.apache.spark.{Logging, SparkConf}
-import org.apache.spark.deploy.{Command, DriverDescription, SparkHadoopUtil}
+import org.apache.spark.deploy.{DriverDescription, SparkHadoopUtil}
 import org.apache.spark.deploy.DeployMessages.DriverStateChanged
 import org.apache.spark.deploy.master.DriverState
 import org.apache.spark.deploy.master.DriverState.DriverState
+import org.apache.spark.util.{Clock, SystemClock}
 
 /**
  * Manages the execution of one driver, including automatically restarting the driver on failure.
@@ -59,9 +58,7 @@ private[spark] class DriverRunner(
   // Decoupled for testing
   private[deploy] def setClock(_clock: Clock) = clock = _clock
   private[deploy] def setSleeper(_sleeper: Sleeper) = sleeper = _sleeper
-  private var clock = new Clock {
-    def currentTimeMillis(): Long = System.currentTimeMillis()
-  }
+  private var clock: Clock = new SystemClock()
   private var sleeper = new Sleeper {
     def sleep(seconds: Int): Unit = (0 until seconds).takeWhile(f => {Thread.sleep(1000); !killed})
   }
@@ -190,9 +187,9 @@ private[spark] class DriverRunner(
         initialize(process.get)
       }
 
-      val processStart = clock.currentTimeMillis()
+      val processStart = clock.getTimeMillis()
       val exitCode = process.get.waitFor()
-      if (clock.currentTimeMillis() - processStart > successfulRunDuration * 1000) {
+      if (clock.getTimeMillis() - processStart > successfulRunDuration * 1000) {
         waitSeconds = 1
       }
 
@@ -208,10 +205,6 @@ private[spark] class DriverRunner(
   }
 }
 
-private[deploy] trait Clock {
-  def currentTimeMillis(): Long
-}
-
 private[deploy] trait Sleeper {
   def sleep(seconds: Int)
 }

core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala

@@ -63,7 +63,7 @@ class DAGScheduler(
     mapOutputTracker: MapOutputTrackerMaster,
     blockManagerMaster: BlockManagerMaster,
     env: SparkEnv,
-    clock: org.apache.spark.util.Clock = SystemClock)
+    clock: Clock = new SystemClock())
   extends Logging {
 
   def this(sc: SparkContext, taskScheduler: TaskScheduler) = {
@@ -657,7 +657,7 @@ class DAGScheduler(
       // completion events or stage abort
       stageIdToStage -= s.id
       jobIdToStageIds -= job.jobId
-      listenerBus.post(SparkListenerJobEnd(job.jobId, clock.getTime(), jobResult))
+      listenerBus.post(SparkListenerJobEnd(job.jobId, clock.getTimeMillis(), jobResult))
     }
   }
 
@@ -706,7 +706,7 @@ class DAGScheduler(
         stage.latestInfo.stageFailed(stageFailedMessage)
         listenerBus.post(SparkListenerStageCompleted(stage.latestInfo))
       }
-      listenerBus.post(SparkListenerJobEnd(job.jobId, clock.getTime(), JobFailed(error)))
+      listenerBus.post(SparkListenerJobEnd(job.jobId, clock.getTimeMillis(), JobFailed(error)))
     }
   }
 
@@ -745,7 +745,7 @@ class DAGScheduler(
       logInfo("Missing parents: " + getMissingParentStages(finalStage))
       val shouldRunLocally =
         localExecutionEnabled && allowLocal && finalStage.parents.isEmpty && partitions.length == 1
-      val jobSubmissionTime = clock.getTime()
+      val jobSubmissionTime = clock.getTimeMillis()
       if (shouldRunLocally) {
         // Compute very short actions like first() or take() with no parent stages locally.
         listenerBus.post(
@@ -871,7 +871,7 @@ class DAGScheduler(
       logDebug("New pending tasks: " + stage.pendingTasks)
       taskScheduler.submitTasks(
         new TaskSet(tasks.toArray, stage.id, stage.newAttemptId(), stage.jobId, properties))
-      stage.latestInfo.submissionTime = Some(clock.getTime())
+      stage.latestInfo.submissionTime = Some(clock.getTimeMillis())
     } else {
       // Because we posted SparkListenerStageSubmitted earlier, we should post
       // SparkListenerStageCompleted here in case there are no tasks to run.
@@ -940,12 +940,12 @@ class DAGScheduler(
 
     def markStageAsFinished(stage: Stage, errorMessage: Option[String] = None) = {
       val serviceTime = stage.latestInfo.submissionTime match {
-        case Some(t) => "%.03f".format((clock.getTime() - t) / 1000.0)
+        case Some(t) => "%.03f".format((clock.getTimeMillis() - t) / 1000.0)
         case _ => "Unknown"
       }
       if (errorMessage.isEmpty) {
         logInfo("%s (%s) finished in %s s".format(stage, stage.name, serviceTime))
-        stage.latestInfo.completionTime = Some(clock.getTime())
+        stage.latestInfo.completionTime = Some(clock.getTimeMillis())
       } else {
         stage.latestInfo.stageFailed(errorMessage.get)
         logInfo("%s (%s) failed in %s s".format(stage, stage.name, serviceTime))
@@ -971,7 +971,7 @@ class DAGScheduler(
                     markStageAsFinished(stage)
                     cleanupStateForJobAndIndependentStages(job)
                     listenerBus.post(
-                      SparkListenerJobEnd(job.jobId, clock.getTime(), JobSucceeded))
+                      SparkListenerJobEnd(job.jobId, clock.getTimeMillis(), JobSucceeded))
                   }
 
                   // taskSucceeded runs some user code that might throw an exception. Make sure
@@ -1187,7 +1187,7 @@ class DAGScheduler(
     }
     val dependentJobs: Seq[ActiveJob] =
       activeJobs.filter(job => stageDependsOn(job.finalStage, failedStage)).toSeq
-    failedStage.latestInfo.completionTime = Some(clock.getTime())
+    failedStage.latestInfo.completionTime = Some(clock.getTimeMillis())
     for (job <- dependentJobs) {
       failJobAndIndependentStages(job, s"Job aborted due to stage failure: $reason")
     }
@@ -1242,7 +1242,7 @@ class DAGScheduler(
     if (ableToCancelStages) {
       job.listener.jobFailed(error)
       cleanupStateForJobAndIndependentStages(job)
-      listenerBus.post(SparkListenerJobEnd(job.jobId, clock.getTime(), JobFailed(error)))
+      listenerBus.post(SparkListenerJobEnd(job.jobId, clock.getTimeMillis(), JobFailed(error)))
     }
   }
 

core/src/main/scala/org/apache/spark/scheduler/TaskSetManager.scala

@@ -51,7 +51,7 @@ private[spark] class TaskSetManager(
     sched: TaskSchedulerImpl,
     val taskSet: TaskSet,
     val maxTaskFailures: Int,
-    clock: Clock = SystemClock)
+    clock: Clock = new SystemClock())
   extends Schedulable with Logging {
 
   val conf = sched.sc.conf
@@ -166,7 +166,7 @@ private[spark] class TaskSetManager(
   // last launched a task at that level, and move up a level when localityWaits[curLevel] expires.
   // We then move down if we manage to launch a "more local" task.
   var currentLocalityIndex = 0    // Index of our current locality level in validLocalityLevels
-  var lastLaunchTime = clock.getTime()  // Time we last launched a task at this level
+  var lastLaunchTime = clock.getTimeMillis()  // Time we last launched a task at this level
 
   override def schedulableQueue = null
 
@@ -281,7 +281,7 @@ private[spark] class TaskSetManager(
       val failed = failedExecutors.get(taskId).get
 
       return failed.contains(execId) &&
-        clock.getTime() - failed.get(execId).get < EXECUTOR_TASK_BLACKLIST_TIMEOUT
+        clock.getTimeMillis() - failed.get(execId).get < EXECUTOR_TASK_BLACKLIST_TIMEOUT
     }
 
     false
@@ -428,7 +428,7 @@ private[spark] class TaskSetManager(
     : Option[TaskDescription] =
   {
     if (!isZombie) {
-      val curTime = clock.getTime()
+      val curTime = clock.getTimeMillis()
 
       var allowedLocality = maxLocality
 
@@ -459,7 +459,7 @@ private[spark] class TaskSetManager(
             lastLaunchTime = curTime
           }
           // Serialize and return the task
-          val startTime = clock.getTime()
+          val startTime = clock.getTimeMillis()
           val serializedTask: ByteBuffer = try {
             Task.serializeWithDependencies(task, sched.sc.addedFiles, sched.sc.addedJars, ser)
           } catch {
@@ -674,7 +674,7 @@ private[spark] class TaskSetManager(
           return
         }
         val key = ef.description
-        val now = clock.getTime()
+        val now = clock.getTimeMillis()
         val (printFull, dupCount) = {
           if (recentExceptions.contains(key)) {
             val (dupCount, printTime) = recentExceptions(key)
@@ -706,7 +706,7 @@ private[spark] class TaskSetManager(
     }
     // always add to failed executors
     failedExecutors.getOrElseUpdate(index, new HashMap[String, Long]()).
-      put(info.executorId, clock.getTime())
+      put(info.executorId, clock.getTimeMillis())
     sched.dagScheduler.taskEnded(tasks(index), reason, null, null, info, taskMetrics)
     addPendingTask(index)
     if (!isZombie && state != TaskState.KILLED && !reason.isInstanceOf[TaskCommitDenied]) {
@@ -821,7 +821,7 @@ private[spark] class TaskSetManager(
     val minFinishedForSpeculation = (SPECULATION_QUANTILE * numTasks).floor.toInt
     logDebug("Checking for speculative tasks: minFinished = " + minFinishedForSpeculation)
     if (tasksSuccessful >= minFinishedForSpeculation && tasksSuccessful > 0) {
-      val time = clock.getTime()
+      val time = clock.getTimeMillis()
       val durations = taskInfos.values.filter(_.successful).map(_.duration).toArray
       Arrays.sort(durations)
       val medianDuration = durations(min((0.5 * tasksSuccessful).round.toInt, durations.size - 1))

core/src/main/scala/org/apache/spark/util/Clock.scala

@@ -21,9 +21,47 @@ package org.apache.spark.util
  * An interface to represent clocks, so that they can be mocked out in unit tests.
  */
 private[spark] trait Clock {
-  def getTime(): Long
+  def getTimeMillis(): Long
+  def waitTillTime(targetTime: Long): Long
 }
 
-private[spark] object SystemClock extends Clock {
-  def getTime(): Long = System.currentTimeMillis()
+/**
+ * A clock backed by the actual time from the OS as reported by the `System` API.
+ */
+private[spark] class SystemClock extends Clock {
+
+  val minPollTime = 25L
+
+  /**
+   * @return the same time (milliseconds since the epoch)
+   *         as is reported by `System.currentTimeMillis()`
+   */
+  def getTimeMillis(): Long = System.currentTimeMillis()
+
+  /**
+   * @param targetTime block until the current time is at least this value
+   * @return current system time when wait has completed
+   */
+  def waitTillTime(targetTime: Long): Long = {
+    var currentTime = 0L
+    currentTime = System.currentTimeMillis()
+
+    var waitTime = targetTime - currentTime
+    if (waitTime <= 0) {
+      return currentTime
+    }
+
+    val pollTime = math.max(waitTime / 10.0, minPollTime).toLong
+
+    while (true) {
+      currentTime = System.currentTimeMillis()
+      waitTime = targetTime - currentTime
+      if (waitTime <= 0) {
+        return currentTime
+      }
+      val sleepTime = math.min(waitTime, pollTime)
+      Thread.sleep(sleepTime)
+    }
+    -1
+  }
 }

core/src/main/scala/org/apache/spark/util/ManualClock.scala

@@ -0,0 +1,69 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.util
+
+/**
+ * A `Clock` whose time can be manually set and modified. Its reported time does not change
+ * as time elapses, but only as its time is modified by callers. This is mainly useful for
+ * testing.
+ *
+ * @param time initial time (in milliseconds since the epoch)
+ */
+private[spark] class ManualClock(private var time: Long) extends Clock {
+
+  /**
+   * @return `ManualClock` with initial time 0
+   */
+  def this() = this(0L)
+
+  def getTimeMillis(): Long =
+    synchronized {
+      time
+    }
+
+  /**
+   * @param timeToSet new time (in milliseconds) that the clock should represent
+   */
+  def setTime(timeToSet: Long) =
+    synchronized {
+      time = timeToSet
+      notifyAll()
+    }
+
+  /**
+   * @param timeToAdd time (in milliseconds) to add to the clock's time
+   */
+  def advance(timeToAdd: Long) =
+    synchronized {
+      time += timeToAdd
+      notifyAll()
+    }
+
+  /**
+   * @param targetTime block until the clock time is set or advanced to at least this time
+   * @return current time reported by the clock when waiting finishes
+   */
+  def waitTillTime(targetTime: Long): Long =
+    synchronized {
+      while (time < targetTime) {
+        wait(100)
+      }
+      getTimeMillis()
+    }
+
+}